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Number of times n can be written as sum of a minimal set of primes.
1

%I #3 Mar 30 2012 18:50:49

%S 1,1,1,1,1,1,1,1,2,1,1,1,2,1,2,1,2,1,2,1,3,1,3,1,3,6,2,1,3,1,2,1,4,7,

%T 4,1,2,1,3,1,4,1,3,1,4,1,5,1,4,14,3,1,5,1,3,16,4,1,6,1,3,1,5,20,6,1,2,

%U 1,5,1,6,1,5,1,5,27,7,1,4,1,5,1,8,1,5,28,4,1,9,1,4,32,5,35,7,1,3,1,6,1,8,1

%N Number of times n can be written as sum of a minimal set of primes.

%C A051034 gives the minimal number of primes needed to sum to n;

%C a(A000040(n)) = 1; a(2*k) = A002375(k) for k>2.

%e A051034(25) = 2: a(25) = #{2+23}=1;

%e A051034(26) = 2: a(26) = #{3+23, 7+19, 13+13} = 3;

%e A051034(27) = 3: a(27) = #{3+5+19, 3+7+17, 3+11+13, 5+5+17,

%e 5+11+11, 7+7+13} = 6;

%e A051034(28) = 2: a(28) = #{5+23, 11+17} = 2;

%e A051034(29) = 1: a(29) = #{29} = 1.

%K nonn

%O 2,9

%A _Reinhard Zumkeller_, Mar 29 2005